Tendinous chords, scientifically known as chordae tendineae, are strong, fibrous, string-like structures located within the heart. Often referred to as “heart strings,” these cords play a specialized role in maintaining the heart’s efficient function. They are found in the ventricles, where they connect the flaps of the atrioventricular valves to small muscular projections. These chords attach the tricuspid valve in the right ventricle and the mitral valve in the left ventricle to their papillary muscles. They are primarily composed of collagen, along with some elastin and specialized cells.
Their Essential Role in Heart Function
The primary function of tendinous chords is to ensure the proper, one-way flow of blood through the heart. They achieve this by working in close coordination with the papillary muscles during the heart’s pumping cycle. As the ventricles contract and push blood out, the atrioventricular valves must close tightly to prevent backflow.
During ventricular contraction, a phase known as systole, the pressure inside the ventricles rises significantly. This increased pressure could force the delicate valve leaflets to invert or prolapse. To counteract this, the papillary muscles contract simultaneously with the ventricular walls.
The contraction of the papillary muscles pulls on the tendinous chords. This tension keeps the valve leaflets firmly closed, much like the ropes of a parachute prevent its canopy from turning inside out under pressure. This mechanism ensures that the mitral and tricuspid valves remain sealed, preventing any backflow of blood into the atria.
This coordinated action is crucial for maintaining the heart’s pumping efficiency. By preventing regurgitation, or the backward leakage of blood, the tendinous chords ensure blood is propelled forward into the major arteries for circulation. Without this control, the heart would have to work harder to move the same amount of blood, impacting overall cardiovascular health.
When Chords Don’t Function Properly
When tendinous chords are compromised, their ability to support the heart valves is impaired, leading to various cardiac issues. Damage can manifest as a rupture, elongation, or weakening of these fibrous structures. Such problems can arise from several causes, including degenerative conditions, infections of the heart valves, physical trauma to the chest, or age-related weakening.
Dysfunction of tendinous chords commonly results in valvular insufficiency or regurgitation. This means the affected valve, most frequently the mitral valve, cannot close completely, allowing blood to leak backward into the preceding heart chamber. For instance, if the mitral valve’s chords are damaged, blood can flow from the left ventricle back into the left atrium during contraction.
This backflow of blood places increased strain on the heart, as it must pump harder to compensate for the leaked volume. Over time, this added workload can lead to symptoms such as shortness of breath, fatigue, or heart palpitations. If left unaddressed, the continuous strain can cause the heart to enlarge and weaken, potentially progressing to heart failure.